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Question: What’s the difference between a diffuse traumatic brain injury (TBI) and a focal one?

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Answer: There will be different ICD-10-CM code sets for each type of TBI, but there are more differences than merely code choice.

A diffuse TBI, also known as a diffuse axonal injury (DAI), is marked by “widespread damage to the brain’s white matter,” according to the National Institute of Neurologic Disorders and Stroke. “DAI can disrupt and break down communication among nerve cells in the brain. It also leads to the release of brain chemicals that can cause further damage.”

To report a diffuse TBI, you’ll look to the S06.2X- (Diffuse traumatic brain injury) code category.

A focal TBI features damage to one specific area of the brain. The symptoms of a focal TBI will depend on the area of the brain that the injury affects. Many focal TBIs have their own codes.

To report a focal TBI, you’ll look to the S06.3- (Focal traumatic brain injury) code set. In this set, you’ll find specific codes for focal TBIs such as contusion and laceration of the right cerebrum (S06.31-) and traumatic hemorrhage of the left cerebrum (S06.35-).

There’s more: Once you settle on whether the TBI was diffuse or focal, you’ll need to start working on assigning the other characters that the code will need for payer acceptance.

The 6^th character for either a diffuse or traumatic TBI relays the same information: Loss of consciousness (LOC) time, if any. The 6^th character digits range from “0” (without loss of consciousness) to “9” (with loss of consciousness of unspecified duration). In between, there are codes to diagnose different LOC types, from 30 minutes or less to more than 24 hours, and even for TBIs resulting in death. So if the encounter notes indicate that a patient suffered a diffuse TBI with LOC of 56 minutes, you’d look to S06.2X2- (Diffuse traumatic brain injury with loss of consciousness of 31 minutes to 59 minutes).

But don’t stop at the 6^th character, as all TBI diagnosis codes require a 7^th character to be complete.

As with the 6^th characters, the 7^th characters will be the same whether the TBI is diffuse or focal. Use 7^th character “A” for an initial encounter to treat the TBI, “D” for a subsequent encounter, and “S” for sequela. So if the encounter notes indicate that a patient who suffered a traumatic hemorrhage of the right cerebrum with two hours LOC returns for subsequent care, you’d report S06.343D (Traumatic hemorrhage of right cerebrum with loss of consciousness of 1 hours to 5 hours 59 minutes, subsequent encounter).

Also: All of the TBI entries have a note instructing you to “Use additional code, if applicable, for traumatic brain compression or herniation (S06.A- [Traumatic brain compression and herniation]).”

Chris Boucher, MS, CPC, Senior Development Editor, AAPC